1. Field of Invention. This invention relates to a method and circuit for adjusting the sensitivity of a sensor, like an optical sensor.
2. Background Information. Optical sensors may be used in printers, for example, to check upon the skewness of a document entering the printer, as indicated in the copending application mentioned above. One of the problems in such a printer is that documents of varying thicknesses are processed by the printer. Because the documents have varying thicknesses, the sensing and aligning of such documents is difficult to maintain with fixed gain optical systems in printers. The manufacturing variations such as alignment, parameter variations, dust, scratches, and degradation of optical parts in the optical systems can cause degradation errors. This problem is compounded when the optical parts or light source detector pairs, for example, are mounted on separate moveable parts of the printer.